North Korea has outlined a plan to simultaneously launch four ballistic missiles toward Guam, a U.S. territory in the Pacific Ocean that is home to a major military base.

Officials in the regime say the plan is to have the missiles hit the water from 19 to 25 miles away from Guam, and that the proposal is expected to be presented to leader Kim Jong Un for his approval or rejection within a week.

Details of the threat came a day after Secretary of State Rex Tillerson assured Guam’s 7,000 U.S. military personnel and 160,000 residents there is no real threat from North Korea despite its behavior.

“Americans should sleep well at night,” Tillerson told reporters while traveling to Guam on Wednesday.

“Nothing that I have seen and nothing that I know of would indicate that the situation has dramatically changed in the last 24 hours.”

This week, Trump warned North Korea it would face “fire and fury” if it prompted the U.S. to respond with military action.